The following is a discussion of Halachic topics related to the Parsha of the week.
For final rulings, consult your Rav.

The seventh day is a Sabbath day of complete rest... you should
not do any work (Lev. 23:3).

HOW DO WE DETERMINE WHEN AN ITEM BECOMES MUKTZEH?

The verse cited above raises an obvious question: Isn't the word
Shabbason (complete rest) superfluous? Is it not sufficient to
simply command: "The seventh day is a Sabbath day... you should
not do any work." What is added by the word Shabbason? The
Ramban (1) answers that the words "you should not do any work"
refer to the prohibition against any of the thirty-nine
Biblically forbidden Shabbos Labors. But the word Shabbason
refers to the rabbinical obligation to enact shvusim, additional
restrictive measures to ensure a superior quality of "rest"
beyond that which is achieved by refraining from the
thirty-nine forbidden Shabbos Labors. One such measure is the
prohibition of muktzeh, which severely curtails the types of
objects which may be moved on Shabbos. By decreeing that there
are many objects which are "off limits", our Sages ensured a
"complete rest" on Shabbos (2).

It is not within the purview of this Discussion to cover all of
the complexities of muktzeh. Instead, we will focus on the
rationale behind the classification of muktzeh items: How and
why does an item becomes muktzeh? (3).

WHAT DOES MUKTZEH MEAN?

Muktzeh means "set apart". Generally speaking, items which are
prepared or designated for use on Shabbos are not muktzeh. Items
which - for one of several reasons - are not ready or designated
to be used on Shabbos are muktzeh.

Although there are many criteria for determining whether or not
an item is muktzeh, for the sake of our Discussion we will group
them into two basic types: a) Severe (chamur) muktzeh - items
which are "set apart" before Shabbos because they will
definitely not be used on Shabbos. [This includes items which
are classified as "non utensils", such as a rock, as well as
items which are classified as "delicate" or "precision"
utensils, such as a ritual slaughterer's knife, which will not
be used for any permitted Shabbos activity, because it is so
easily damaged], and b) Light (kal) muktzeh - items which are
set apart because they are normally used for activities which
are prohibited on Shabbos, but may, on occasion, be used for a
permitted Shabbos activity, e.g., scissors.

WHAT DIFFERENCE IS THERE BETWEEN THE TWO TYPES OF MUKTZEH?

Severe muktzeh may never (4) be moved in a normal,
straightforward manner (5), while light muktzeh may be moved in
either one of the following two cases:

a) If the muktzeh item is needed in order to perform a permissible activity, or

b) if the place which the muktzeh item occupies is needed in order to perform a permissible activity.

Let us explain:

In order to perform a permitted activity: A hammer, a typical
light muktzeh, may be used in order to crack nuts. A sewing
needle, another light muktzeh, may be used to remove a splinter
from one's finger. Since nut-cracking and splinter removal are
permitted activities, a light muktzeh item may be used. [The
poskim (6) note, however, that light muktzeh should only be
employed when no other suitable item is readily available.
Therefore, if a nutcracker and a hammer are equally accessible,
the nutcracker should be used. There is no need, however, to
borrow a nutcracker if a hammer is available.]

If the place which the muktzeh item occupies is needed - If a
tool was left on a bed and the bed is needed for sleeping, or if
scissors were left on a chair and the chair is needed for
sitting, the light muktzeh item may be picked up and removed,
since the muktzeh article is in the way of a need which is
permitted to be met on Shabbos. Also, if the light muktzeh is in
the way of a permitted item, e.g., a hammer is on a bookshelf
and it is blocking a book, it is permitted to move the hammer in
order to reach the book. [It is questionable if one is allowed
to move a light muktzeh item which is simply creating a clutter
but not actually interfering with a permissible activity, e.g. a
hammer left lying on the mantel. Contemporary poskim disagree
whether moving it is permitted (7).]

SOME COMMON EXAMPLES OF SEVERE MUKTZEH:

Animals (8),

bar of soap (9),

camera,

detergent,

eye-shadow,

flour,

glue,

light bulb,

lulav (10),

matches (11),

mascara,

money,

nutshells,

raw barley,

roll of silver foil or toilet paper (12),

shatnez garment (13),

shofar (14),

Vaseline,

toothpaste.

SOME COMMON EXAMPLES OF LIGHT MUKTZEH:

Car (15),

car key (16),

comb,

crayon,

empty wallet,

empty kettle,

fan (17),

flashlight (18),

garden hose,

hammer,

mop and pail,

pen (19),

pencil sharpener,

potato peeler,

rolling pin,

ruler,

scales,

scissors,

screwdriver,

stapler,

store catalog (20),

telephone book (21),

toaster,

whistle.

SOME ITEMS WHOSE STATUS IS QUESTIONABLE--SEVERE OR LIGHT MUKTZEH:

There are some muktzeh items - an unlit candle, a
candlestick, lipstick, copy paper - whose status is
debatable (22). On the one hand, these items are utensils like
the light muktzeh items listed above, but unlike those light
muktzeh items they do not have a function which is permitted on
Shabbos [e.g., there is nothing permissible that can be done
with a tube of lipstick on Shabbos]. Because they do not, some
poskim (23) consider them as severe muktzeh, and forbid moving
them even if the place they occupy is needed to perform a
permissible activity. Other poskim (24) hold that it is not
necessary that they have a function which is permissible on
Shabbos and they may be classified as light muktzeh since they
are, after all, utensils.

Under extenuating circumstances one may be lenient and consider
these items as light muktzeh (25).

10 Mishnah Berurah 308:25 (because it is not a utensil); Aruch
Hashulchan 308:17 (because it is "delicate").

11 The muktzeh status of matches is questionable. Some (Harav M.
Feinstein) consider them severe muktzeh; others (Harav S. Z.
Auerbach; Harav B. Silber) rule them to be light muktzeh, while
others hold they are a questionable muktzeh, similar to the
those listed below. See Meorei Eish pg. 37, Shmiras Shabbos
K'hilchasah pg. 154 and 239, Sefer Tiltulei Shabbos pg. 82 and
Shalmei Yehudah pg. 74 for the various views and reasons.

12 Shalmei Yehudah pg. 98 and pg. 171.

13 OC 308:47.

14 Although Rama 308:4 considers a shofar to be light muktzeh,
contemporary poskim (Harav S.Y. Elyashiv - Shalmei Yehudah pg.
32; Harav S.Z. Auerbach (Shmiras Shabbos K'hilchasah pg. 361 and
in Tikunim U'milluim pg. 32) agree that nowadays a shofar is too
"delicate" to be used for anything other than blowing which is
prohibited on Shabbos.

15 Igros Moshe OC 5:21-11; Shalmei Yehudah pg. 201.

16 Harav S.Y. Elyashiv (Shalmei Yehudah pg. 202). If the key
opens the door, then it is not muktzeh. See Tikunim U'miluim pg.
254 where Harav S.Z. Auerbach holds that if a light goes on when
the car door opens, then the keys are severe muktzeh.

26 Some poskim (Chazon Ish OC 43:17) hold that they are severe
muktzeh, while other poskim (Igros Moshe OC 5:21-13; 22-12) hold
that they are not muktzeh at all. See also Mishnah Berurah
308:8; 308:168 and Shalmei Yehudah pg. 71.

27 Mishnah Berurah 308:35 seems to hold that a button that is
going to be reattached is not muktzeh. Igros Moshe OC 5:22-20
disagrees and prohibits all buttons. Harav S.Z. Auerbach
(Shmiras Shabbos K'hilchasah pg. 178) and Harav S.Y. Elyashiv
(Shalmei Yehudah pg. 80) hold that according to the basic
halachah it is permissible but it is proper to be stringent.